The disclosure relates to a solenoid valve having a solenoid armature which is operatively connected to a sealing element of the solenoid valve in order to move the same, and an armature opposing piece which engages at least in certain areas in a receptacle opening in the solenoid armature.
Solenoid valves of the type mentioned at the beginning are known from the prior art. They are used, for example, for driver assistance devices, that is to say in particular in conjunction with ABS systems, TCS systems or ESP systems. The solenoid valves are embodied, for example, as 2/2-way valves, which can be open in the currentless state or else closed in the currentless state. In such a solenoid valve, the sealing element is usually arranged in such a way that it can be moved in its axial direction in order to interact, in a closed position, with a valve seat of the solenoid valve in a seal-forming fashion and therefore to interrupt a continuous fluid connection through the solenoid valve. If, on the other hand, the sealing element is moved into a release position, it releases the valve seat so that fluid can flow through the solenoid valve, and the continuous fluid connection is therefore produced. The sealing element is moved by means of a solenoid armature. For this purpose, the solenoid armature is arranged in the region of at least one coil. If the coil is currentless, the solenoid armature is in its home position, wherein this home position can be the closed position (solenoid valve which is closed in the currentless state) or the released position (solenoid valve which is opened in the currentless state). For this purpose, the sealing element is operatively connected to the solenoid valve, and therefore has, for example, a rigid connection thereto.
The solenoid armature forms, together with the armature opposing piece, a magnetic part of the solenoid valve. In this context, the solenoid armature and the armature opposing piece are arranged with respect to one another in such a way that the end faces of the two elements face one another. For example, the solenoid armature and the armature opposing piece are oriented in such a way that a respective longitudinal axis runs coaxially with respect to or in parallel with a longitudinal axis of the solenoid valve. The armature opposing piece can be assigned to the coil of the solenoid valve.
From the prior art it is known that the end faces of the solenoid armature and armature opposing piece are of flat design and at the same time run substantially parallel with one another. However, it is also known to provide either the solenoid armature or the armature opposing piece with a receptacle opening, wherein the respective other element engages, at least in certain areas, in this receptacle opening. It is therefore possible to provide, for example, that the solenoid armature has the receptacle opening, and the armature opposing piece engages therein at least in certain areas. Conversely, it is, of course, also possible for the armature opposing piece to have the receptacle opening, the solenoid armature engaging therein at least in certain areas.
In this context there is merely provision that the engagement, at least in certain areas, in at least one position of the solenoid armature or of the sealing element is ensured. Accordingly, it is also possible to provide that in at least one position the armature opposing piece is arranged completely outside the receptacle opening in the solenoid armature. What is referred to as a plunger stage is formed by the receptacle opening of the solenoid armature and the armature opposing piece which engages therein (or the receptacle opening of the armature piece with the solenoid armature which is arranged therein at least in certain areas), that is to say the engagement of the solenoid armature and the armature opposing piece in one another.
From the prior art it is known to embody the plunger stage as a single plunger stage or as a double plunger stage or as a multiple plunger stage. In the former case the receptacle opening has constant dimensions over its axial extent, at least in the area which accommodates the armature opposing piece. In contrast, in the case of the double plunger stage there is provision for the receptacle opening to be formed with two different dimensions over its axial extent, wherein the armature opposing piece is matched in each case to these dimensions, that is to say is also present with different dimensions. Of course, it is also possible to form a multiple plunger stage with any desired number of gradations of the dimensions.
In the arrangement of the armature opposing piece in the receptacle opening of the solenoid armature, the armature opposing piece and the solenoid armature must not be in contact with one another in the radial direction. For this reason, a radial gap, which is present, for example, as an annular gap, is formed between the two elements. For this reason, in such a plunger stage it is necessary to ensure precise guidance of the solenoid armature. This usually results in stringent tolerance requirements for many parts of the solenoid valve, in particular for the solenoid armature and the armature opposing piece, as well as for the guidance or bearing of the solenoid armature in the solenoid valve. For this reason, the manufacture of such a solenoid valve is comparatively complex and therefore costly.